The development of touch technology generally aims at low cost, high yield, large size and high reliability etc. To fulfill these objectives, an ITO Sensor and a Cover lens may be integrated together, even with a thin-film transistor (TFT), on terms of process and technology, in order to reduce the production cost, lower the thickness of products, and eliminate defects on bonding.
With regard to materials used in touch technology, organic or inorganic substituting materials of ITO and flexible film and substrate may be developed, or relatively expensive toughened glass boards or polymethyl methacrylate (PMMA) plastic boards can be replaced with new plastic materials for the Cover lens. With regard to structures, built-in touch structures, such as On-Cell touch, In-Cell touch and the like, have been developed. The In-Cell touch structure is highly integrated, which leads to a low yield. However, a touch device with the In-Cell touch structure is in general thin in thickness and light in weight.
FIG. 1, FIG. 2 and FIG. 3 respectively show three types of common In-Cell touch technologies, including photosensitive touch technology, capacitive touch technology and resistive touch technology.
FIG. 1 shows the photosensitive touch technology, which can be embodied with multiple specific methods, wherein a typical one is that a relatively high current is formed in a photosensitive switch on a first substrate 1 under the irradiation of a laser pen, and the touch position can be determined by determining the position of the switch in which the current is generated.
FIG. 2 shows the capacitive touch technology. Namely, after a second substrate 2 is pressed, the thickness of a liquid crystal layer at the pressed position is changed, as a result of which the corresponding liquid crystal capacitance value is also changed, and the touch position can be determined by determining the position where the liquid crystal capacitance changes.
FIG. 3 shows the resistive touch technology. Namely, after the second substrate 2 is pressed, a conductive layer of the second substrate 2 is respectively in contact with a conductive pad connected with a transverse sensing line and a conductive pad connected with a longitudinal sensing line on the first substrate 1, and the touch position can be determined by determining the positions on the transverse sensing line and the longitudinal sensing line where the short circuit(s) occur(s).
However, it is difficult for the In-Cell touch technology in the prior art to be applied on a large-sized panel due to low pixel aperture ratio, and complicated touch driving circuit.